DTC B0040 Coupe
Circuit Description
When the ignition switch is turned ON and during vehicle operation, the SDM
performs tests to detect system faults. One test the SDM performs is to monitor
the inflator module high circuit and inflator module low circuit voltage difference.
By monitoring voltage difference, the SDM is able to calculate the loop resistance.
A low loop resistance indicates the two circuits are shorted together.
DTC Parameters
DTC B0040 can be set when the loop resistance is low. The following conditions
must be met to set this DTC:
| • | Ignition voltage is present at the SDM and continuous. |
| • | The deployment loop resistance is under 1.3 ohms. |
| • | Fault is present for half a second. |
Action Taken
| • | The air bag telltale will be ON. |
Diagnostic Aids
| • | When attempting to diagnose an intermittent loop fault, use the scan tool
to monitor current DTCs. Wiggle wires and check connections while watching for a
current DTC to appear and/or disappear on the scan tool. |
| • | Always start diagnosis of SIR DTCs with an inspection of wiring and components
for visible damage. |
| • | A malfunctioning shorting bar at the inflator module harness could cause
this DTC. |
DTC B0040 Sedan
Circuit Description
When the ignition switch is turned ON and during vehicle operation, the SDM
performs tests to detect system faults. One test the SDM performs is to monitor
the inflator module high circuit and inflator module low circuit voltage difference.
By monitoring voltage difference, the SDM is able to calculate the loop resistance.
A low loop resistance indicates the two circuits are shorted together.
DTC Parameters
DTC B0040 can be set when the loop resistance is low. The following conditions
must be met to set this DTC:
| • | Ignition voltage is present at the SDM and continuous. |
| • | The deployment loop resistance is under 1.3 ohms. |
| • | Fault is present for half a second. |
Action Taken
| • | The air bag telltale will be ON. |
Diagnostic Aids
| • | When attempting to diagnose an intermittent loop fault, use the scan tool
to monitor current DTCs. Wiggle wires and check connections while watching for a
current DTC to appear and/or disappear on the scan tool. |
| • | Always start diagnosis of SIR DTCs with an inspection of wiring and components
for visible damage. |
| • | A malfunctioning shorting bar at the inflator module harness could cause
this DTC. |
